1. Field of the Invention
The present invention relates to a bag making apparatus and, more particularly, to a bag making, filling and packaging apparatus including means for intermittently delivering a packaging film of a predetermined length, while forming the film into a tubular film by a bag making cylindrical body; filling the tubular packaging film with a material to be packaged; and clamping the tubular film by closing a pair of opposed transverse sealing devices to heat seal the tubular film in the width direction. More particularly, the invention relates to such an apparatus in which a sealed portion of the packaging film is cooled after heat sealing.
2. Description of Background and Pertinent Information
Bag making, filling and packaging apparatus of the above-mentioned type have been known. For instance, Japanese Laid-Open Patent Application (KOKAI) No. 50-78487 (1975) discloses an apparatus in which blow-off ports are provided on the upper and lower sides of transverse sealing devices, the ports being opened toward a sealed portion of a packaging film, and cooling air is blown from the blow-off ports immediately after heat sealing, thereby cooling the sealed portion.
3. Problems Solved by the Invention
In such a conventional bag making, filling and packaging apparatus, however, each of the blow-off ports is disposed remote from the transverse sealing device so as not to interfere with the forward and backward movements of the sealing devices. Consequently, a relatively long time is taken to completely cool the sealed portion and a high-speed operation of the apparatus cannot be achieved. In addition, shortening the cooling time to obviate this problem results in incomplete cooling, which tends to cause delamination of the sealed portion, particularly where the material to be packaged is heavy.
This type of bag making, filling and packaging apparatus has the further problem that the surface of the sealed portion is rugged, and is not smooth, resulting in a poorer appearance and a further lowered sealing effect.